As part of our 10 Most Influential People in Family Life gallery, we spoke with What to Expect When You're Expecting author Heidi Murkoff about moms' presence online, what readers would never believe about her, and why she sometimes (only in "moments of baby-fever delirium") wants another toddler of her own.

Parent & Child: In a recent interview, you said that What To Expect When You’re Expecting is never going to be a finished book. What are some of the biggest changes you’ve seen since it was first published almost 30 years ago?Heidi Murkoff: You really don’t have to look any further than the book’s cover to see how pregnancy has changed. First, you had a mom-to-be, hiding her belly under a polyester pup tent, sitting expectantly (or miserably, I could make a case for either) in a rocking chair . . . waiting. Then you had the same mom-to-be, still in the rocking chair, but wearing pants. Finally, you have the fourth edition mama. She’s off her rocker, she’s on her feet, she’s wearing jeans and a sweater that hug her beautiful belly — and, most importantly, she’s happy, smiling, and confident. She’s wearing her belly proudly, celebrating her pregnancy and her pregnant body. She is a metaphor for how pregnancy has changed, and how pregnant women have changed.

P&C: How has the Internet altered the way you give advice?

Murkoff: Back in the days when dinosaurs and snail mail roamed the earth, my connection to moms was limited to writing the books and reading letters from readers. Now, I can interact with moms and a growing number of dads on Facebook, Twitter, and WhatToExpect.com. The absolute highlight of every day is sitting down on my sofa with my iPad after dinner and answering questions (I answer them all!), gobbling up baby photos and videos, talking shop with parents. When I needed bellies of all shapes and sizes for the fourth edition of Expecting, moms online sent me their bumps.

P&C: Some people criticized earlier editions for their strictness about prenatal nutrition. You listened and revised. Are you a careful eater?

Murkoff: They were absolutely right. [The Best Odds Diet] had the best of intentions — healthier pregnancies and healthier babies through a healthier diet — but not the best of results. Instead of aiming for a healthier diet, moms usually ended up running screaming for the nearest fast food fries. The Pregnancy Diet is far more forgiving and realistic, plus far more fun to follow. You can eat well and still feed yourself and baby well. That’s pretty much the nutrition model [my husband] Erik and I follow, and so do our kids, even though I don’t feed them anymore. Last night for dinner, I ate buffalo steak, bloody rare because I’m not expecting, and salad.

P&C:Finish this sentence: My readers would never believe that I . . .

Murkoff: [ . . . that I] didn’t always know what to expect when you’re expecting. Or what to expect the first year, or the second year. Like most moms, I was made on the job, one sleepless night, one dirty diaper, one colicky afternoon at a time. Oh, and I didn’t have any of my books to read.

P&C: Do you or your husband make any on-screen cameos in the What to Expect movie, premiering on May 18?

Murkoff: No — it’s such an amazing (and improbably good-looking) cast, I thought I’d leave the acting to the actors. But we did have the chance to make our contributions from behind the scenes.

P&C: Will the franchise ever grow to include What to Expect books covering later childhood and adolescence?

Murkoff: I think I’ll stick to my little pregnancy and early childhood niche for now. Parents of tweens and teens who ask for a What to Expect book to help them through adolescence should just use What to Expect the Second Year and do a little creative editing. Toddlers and teenagers are pretty much the same creature; there is overlap in behaviors with power struggles and temper tantrums, and the same strategies apply, such as choosing your battles, setting limits, being consistent, loving them unconditionally, and keeping your sense of humor.

P&C: You have two grown children. Does being immersed in the world of babies all the time ever make you want another of your own?

Murkoff: Every day! In fact, Erik and I have even kicked the idea around in moments of baby-fever delirium. We had our babies so early on, at least by today’s standards, that it would be interesting to experience parenting from a position of more knowledge and maturity. That said, we’ve become attached to a full night’s sleep and other baby-free luxuries, and can only hope for quick turnaround from our newly married daughter and son-in-law.

P&C:What is the most important lesson your own children have taught you?

Murkoff: To stop and smell the roses — and the babies. Our lives are so busy, and seem always to be getting busier. But kids, even as they make life more chaotic and frenetic, give you a reason to jump off the hamster wheel every now and again, to slow down and appreciate the little things.